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Abstract:

A transmission is provided having an input member, an output member, at
least four planetary gear sets, a plurality of coupling members and a
plurality of torque transmitting devices. Each of the planetary gear sets
includes first, second and third members. The torque transmitting devices
include clutches and brakes actuatable in combinations of three to
establish a plurality of forward gear ratios and one reverse gear ratio.

Claims:

1. A transmission comprising: an input member; an output member; first,
second, third and fourth planetary gear sets each having first, second
and third members; four interconnecting members continuously
interconnecting a member of the first, second, third and fourth planetary
gear sets with another member of the first, second, third and fourth
planetary gear sets; and six torque transmitting mechanisms wherein three
of the six torque transmitting mechanisms are each selectively engageable
to interconnect at least one of the first, second and third members with
at least one other of the first, second, third members and wherein three
of the six torque transmitting mechanisms are each selectively engageable
to interconnect at least one of the first, second and third members with
the stationary member, and wherein the six torque transmitting mechanisms
are selectively engageable in combinations of at least three to establish
a plurality of forward speed ratios and at least one reverse speed ratio
between the input member and the output member.

2. The transmission of claim 1 wherein the four interconnecting members
further comprises a first interconnecting member continuously
interconnecting the second member of the first planetary gear set with
the third member of the third planetary gear set, a second
interconnecting member continuously interconnecting the first member of
the second planetary gear set with the first member of the fourth
planetary gear set, a third interconnecting member continuously
interconnecting the second member of the second planetary gear set with
the first member of the third planetary gear set, and a fourth
interconnecting member continuously interconnecting the second member of
the third planetary gear set with the second member of the fourth
planetary gear set.

3. The transmission of claim 1 wherein a first of the six torque
transmitting mechanisms is selectively engageable to interconnect the
first member of the third planetary gear set and the second member of the
second planetary gear set with the third member of the fourth planetary
gear set.

4. The transmission of claim 3 wherein a second of the six torque
transmitting mechanisms is selectively engageable to interconnect the
third member of the third planetary gear set and the second member of the
first planetary gear set with the third member of the fourth planetary
gear set.

5. The transmission of claim 4 wherein a third of the six torque
transmitting mechanisms is selectively engageable to interconnect the
third member of the first planetary gear set and the input member with
the third member of the fourth planetary gear set.

6. The transmission of claim 5 wherein a fourth of the six torque
transmitting mechanisms is selectively engageable to interconnect the
first member of the second planetary gear set with the stationary member.

7. The transmission of claim 6 wherein a fifth of the six torque
transmitting mechanisms is selectively engageable to interconnect the
third member of the second planetary gear set with the stationary member.

8. The transmission of claim 7 wherein a sixth of the six torque
transmitting mechanisms is selectively engageable to interconnect the
first member of the first planetary gear set with the stationary member.

9. The transmission of claim 1 wherein the input member is continuously
connected for common rotation with the third member of the first
planetary gear set.

10. The transmission of claim 1 wherein the output member is continuously
connected for common rotation with the second member of the fourth
planetary gear set and the second member of the third planetary gear set.

11. The transmission of claim 1 wherein the first member of the first
planetary gear set, the third member of the second planetary gear set,
the third member of the third planetary gear set and the third member of
the fourth planetary gear set are sun gears, the second members of the
first, second and fourth planetary gear sets and the first member of the
third planetary gear set are carrier members and the third member of the
first planetary gear set, the first member of the second planetary gear
set, the second member of the third planetary gear set and the first
member of the fourth planetary gear set are ring gears.

12. A transmission comprising: an input member; an output member; first,
second, third and fourth planetary gear sets each having first, second
and third members; a first interconnecting member continuously
interconnecting the second member of the first planetary gear set with
the third member of the third planetary gear set; a second
interconnecting member continuously interconnecting the first member of
the second planetary gear set with the first member of the fourth
planetary gear set; a third interconnecting member continuously
interconnecting the second member of the second planetary gear set with
the first member of the third planetary gear set; a fourth
interconnecting member continuously interconnecting the second member of
the third planetary gear set with the second member of the fourth
planetary gear set; and six torque transmitting mechanisms each
selectively engageable to interconnect at least one of the first, second,
and third members with at least one other of the first, second, third
members and the stationary member, and wherein the six torque
transmitting mechanisms are selectively engageable in combinations of at
least three to establish at least ten forward speed ratios and at least
one reverse speed ratio between the input member and the output member.

13. The transmission of claim 12 wherein a first of the six torque
transmitting mechanisms is selectively engageable to interconnect the
first member of the third planetary gear set and the second member of the
second planetary gear set with the third member of the fourth planetary
gear set.

14. The transmission of claim 13 wherein a second of the six torque
transmitting mechanisms is selectively engageable to interconnect the
third member of the third planetary gear set and the second member of the
first planetary gear set with the third member of the fourth planetary
gear set.

15. The transmission of claim 14 wherein a third of the six torque
transmitting mechanisms is selectively engageable to interconnect the
third member of the first planetary gear set and the input member with
the third member of the fourth planetary gear set.

16. The transmission of claim 15 a fourth of the six torque transmitting
mechanisms is selectively engageable to interconnect the first member of
the second planetary gear set with the stationary member.

17. The transmission of claim 16 wherein a fifth of the six torque
transmitting mechanisms is selectively engageable to interconnect the
third member of the second planetary gear set with the stationary member.

18. The transmission of claim 17 wherein a sixth of the six torque
transmitting mechanisms is selectively engageable to interconnect the
first member of the first planetary gear set with the stationary member.

19. The transmission of claim 12 wherein the input member is continuously
connected for common rotation with the third member of the first
planetary gear set.

20. The transmission of claim 12 wherein the output member is
continuously connected for common rotation with the second member of the
fourth planetary gear set and the second member of the third planetary
gear set.

21. The transmission of claim 12 wherein the first member of the first
planetary gear set, the third member of the second planetary gear set,
the third member of the third planetary gear set and the third member of
the fourth planetary gear set are sun gears, the second members of the
first, second and fourth planetary gear sets and the first member of the
third planetary gear set are carrier members and the third member of the
first planetary gear set, the first member of the second planetary gear
set, the second member of the third planetary gear set and the first
member of the fourth planetary gear set are ring gears.

22. A transmission comprising: an input member; an output member; first,
second, third and fourth planetary gear sets each having a sun gear, a
carrier member and a ring gear, wherein the input member is continuously
connected for common rotation with the ring gear of the first planetary
gear set, and wherein the output member is continuously connected for
common rotation with the carrier member of the fourth planetary gear set
and the ring gear of the third planetary gear set; a first
interconnecting member continuously interconnecting the carrier member of
the first planetary gear set with the sun gear of the third planetary
gear set; a second interconnecting member continuously interconnecting
the ring gear of the second planetary gear set with the ring gear of the
fourth planetary gear set; a third interconnecting member continuously
interconnecting the carrier member of the second planetary gear set with
the carrier member of the third planetary gear set; a fourth
interconnecting member continuously interconnecting the ring gear of the
third planetary gear set with the carrier member of the fourth planetary
gear set; a first torque transmitting mechanism selectively engageable to
interconnect the carrier member of the third planetary gear set and the
carrier member of the second planetary gear set with the sun gear of the
fourth planetary gear set; a second torque transmitting mechanism
selectively engageable to interconnect the sun gear of the third
planetary gear set and the carrier member of the first planetary gear set
with the sun gear of the fourth planetary gear set; a third torque
transmitting mechanism selectively engageable to interconnect the ring
gear of the first planetary gear set and the input member with the sun
gear of the fourth planetary gear set; a fourth torque transmitting
mechanism selectively engageable to interconnect the ring gear of the
second planetary gear set with the stationary member; a fifth torque
transmitting mechanism selectively engageable to interconnect the sun
gear of the second planetary gear set with the stationary member; a sixth
torque transmitting mechanism selectively engageable to interconnect the
sun gear of the first planetary gear set with the stationary member, and
wherein the torque transmitting mechanisms are selectively engageable in
combinations of at least three to establish a plurality of forward speed
ratios and at least one reverse speed ratio between the input member and
the output member.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application
No. 61/594,108 filed Feb. 2, 2012. The disclosure of the above
application is incorporated herein by reference.

FIELD

[0002] The invention relates generally to a multiple speed transmission
having a plurality of planetary gear sets and a plurality of torque
transmitting devices and more particularly to a transmission having ten
or more speeds, at least four planetary gear sets and a plurality of
torque transmitting devices.

BACKGROUND

[0003] The statements in this section merely provide background
information related to the present disclosure and may or may not
constitute prior art.

[0004] A typical multiple speed transmission uses a combination of
friction clutches, planetary gear arrangements and fixed interconnections
to achieve a plurality of gear ratios. The number and physical
arrangement of the planetary gear sets, generally, are dictated by
packaging, cost and desired speed ratios.

[0005] While current transmissions achieve their intended purpose, the
need for new and improved transmission configurations which exhibit
improved performance, especially from the standpoints of efficiency,
responsiveness and smoothness and improved packaging, primarily reduced
size and weight, is essentially constant. Accordingly, there is a need
for an improved, cost-effective, compact multiple speed transmission.

[0006] SUMMARY

[0007] A transmission is provided having an input member, an output
member, four planetary gear sets, a plurality of coupling members and a
plurality of torque transmitting devices. Each of the planetary gear sets
includes first, second and third members. The torque transmitting devices
are for example clutches and brakes.

[0008] In another embodiment of the present invention, the transmission
has a first, second, third and fourth planetary gear sets each having a
sun gear, a carrier member and a ring gear.

[0009] In still another embodiment of the present invention, the input
member is continuously connected for common rotation with the ring gear
of the first planetary gear set.

[0010] In still another embodiment of the present invention, the output
member is continuously connected for common rotation with the carrier
member of the fourth planetary gear set and the ring gear of the third
planetary gear set.

[0011] In still another embodiment of the present invention, a first
interconnecting member continuously interconnects the carrier member of
the first planetary gear set with the sun gear of the third planetary
gear set.

[0012] In yet another embodiment of the present invention, a second
interconnecting member continuously interconnects the ring gear of the
second planetary gear set with the ring gear of the fourth planetary gear
set.

[0013] In yet another embodiment of the present invention, a third
interconnecting member continuously interconnects the carrier member of
the second planetary gear set with the carrier member of the third
planetary gear set.

[0014] In yet another embodiment of the present invention, a fourth
interconnecting member continuously interconnects the ring gear of the
third planetary gear set with the carrier member of the fourth planetary
gear set.

[0015] In yet another embodiment of the present invention, a first torque
transmitting mechanism is selectively engageable to interconnect the
carrier member of the third planetary gear set and the carrier member of
the second planetary gear set with the sun gear of the fourth planetary
gear set.

[0016] In yet another embodiment of the present invention, a second torque
transmitting mechanism is selectively engageable to interconnect the sun
gear of the third planetary gear set and the carrier member of the first
planetary gear set with the sun gear of the fourth planetary gear set.

[0017] In yet another embodiment of the present invention, a third torque
transmitting mechanism is selectively engageable to interconnect the ring
gear of the first planetary gear set and the input member with the sun
gear of the fourth planetary gear set.

[0018] In yet another embodiment of the present invention, a fourth torque
transmitting mechanism is selectively engageable to interconnect the ring
gear of the second planetary gear set with the stationary member.

[0019] In yet another embodiment of the present invention, a fifth torque
transmitting mechanism is selectively engageable to interconnect the sun
gear of the second planetary gear set with the stationary member.

[0020] In yet another embodiment of the present invention, a sixth torque
transmitting mechanism is selectively engageable to interconnect the sun
gear of the first planetary gear set with the stationary member.

[0021] In yet another embodiment of the present invention, the torque
transmitting mechanisms are selectively engageable in combinations of at
least three to establish a plurality of forward speed ratios and at least
one reverse speed ratio between the input member and the output member.

[0022] Further features, aspects and advantages of the present invention
will become apparent by reference to the following description and
appended drawings wherein like reference numbers refer to the same
component, element or feature.

DRAWINGS

[0023] The drawings described herein are for illustration purposes only
and are not intended to limit the scope of the present disclosure in any
way.

[0024] FIG. 1 is a lever diagram of an embodiment of a ten speed
transmission according to the present invention;

[0025]FIG. 2 is a diagrammatic illustration of an embodiment of a ten
speed transmission according to the present invention; and

[0026]FIG. 3 is a truth table presenting the state of engagement of the
various torque transmitting elements in each of the available forward and
reverse speeds or gear ratios of the transmissions illustrated in FIGS.
1, 2 and 3.

DETAILED DESCRIPTION

[0027] The following description is merely exemplary in nature and is not
intended to limit the present disclosure, application, or uses.

[0028] At the outset, it should be appreciated that the embodiments of the
multi-speed automatic transmissions of the present invention have an
arrangement of permanent mechanical connections between the elements of
the four planetary gear sets. For example, a second component or element
of a first planetary gear set is permanently coupled to a third component
or element of the third planetary gear set. A first component or element
of the second planetary gear set is permanently coupled a first component
or element of the fourth planetary gear set. A second component or
element of the second planetary gear set is permanently coupled to a
first component or element of the third planetary gear set. A second
component or element of the third planetary gear set is permanently
coupled to a second component or element of the fourth planetary gear
set.

[0029] Referring now to FIG. 1, an embodiment of a ten speed transmission
10 is illustrated in a lever diagram format. A lever diagram is a
schematic representation of the components of a mechanical device such as
an automatic transmission. Each individual lever represents a planetary
gear set wherein the three basic mechanical components of the planetary
gear are each represented by a node. Therefore, a single lever contains
three nodes: one for the sun gear, one for the planet gear carrier, and
one for the ring gear. The relative length between the nodes of each
lever can be used to represent the ring-to-sun ratio of each respective
gear set. These lever ratios, in turn, are used to vary the gear ratios
of the transmission in order to achieve an appropriate ratios and ratio
progression. Mechanical couplings or interconnections between the nodes
of the various planetary gear sets are illustrated by thin, horizontal
lines and torque transmitting devices such as clutches and brakes are
presented as interleaved fingers. Further explanation of the format,
purpose and use of lever diagrams can be found in SAE Paper 810102, "The
Lever Analogy: A New Tool in Transmission Analysis" by Benford and
Leising which is hereby fully incorporated by reference.

[0030] The transmission 10 includes an input shaft or member 12, a first
planetary gear set 14, a second planetary gear set 16, a third planetary
gear set 18 and a fourth planetary gear set 20 and an output shaft or
member 22. In the lever diagram of FIG. 1, the first planetary gear set
14 has three nodes: a first node 14A, a second node 14B and a third node
14C. The second planetary gear set 16 has three nodes: a first node 16A,
a second node 16B and a third node 16C. The third planetary gear set 18
has three nodes: a first node 18A, a second node 18B and a third node
18C. The fourth planetary gear set 20 has three nodes: a first node 20A,
a second node 20B and a third node 20C.

[0031] The input member 12 is continuously coupled to the third node 14C
of the first planetary gear set 14. The output member 22 is coupled to
the second node 20B of the fourth planetary gear set 20. The second node
14B of the first planetary gear set 14 is coupled to the third node 18C
of the third planetary gear set 18. The first node 16A of the second
planetary gear set 16 is coupled to the first node 20A of the fourth
planetary gear set 20. The second node 16B of the second planetary gear
set 16 is coupled to the first node 18A of the third planetary gear set
18. The second node 18B of the third planetary gear set 18 is coupled to
second node 20B of the fourth planetary gear set 20.

[0032] A first clutch 24 selectively connects the second node 16B of the
second planetary gear set 16 and the first node 18A of the third
planetary gear set 18 with the third node 20C of the fourth planetary
gear set 20. A second clutch 26 selectively connects the second node 14B
of the first planetary gear set 14 and the third node 18C of the third
planetary gear set 18 with the third node 20C of the fourth planetary
gear set 20. A third clutch 28 selectively connects the third node 14C of
the first planetary gear set 14 and the input member 12 with the third
node 20C of the fourth planetary gear set 20. A first brake 30
selectively connects first node 16A of the second planetary gear set 16
and the first node 20A of the fourth planetary gear set 20 with a
stationary member or transmission housing 50. A second brake 32
selectively connects the third node 16C of the second planetary gear set
16 with the stationary member or transmission housing 50. A third brake
34 selectively connects the first node 14A of the first planetary gear
set 14 with the stationary member or transmission housing 50.

[0033] Referring now to FIG. 2, a stick diagram presents a schematic
layout of an embodiment of the ten speed transmission 10 according to the
present invention. In FIG. 2, the numbering from the lever diagram of
FIG. 1 is carried over. The clutches and couplings are correspondingly
presented whereas the nodes of the planetary gear sets now appear as
components of planetary gear sets such as sun gears, ring gears, planet
gears and planet gear carriers.

[0034] For example, the planetary gear set 14 includes a sun gear member
14A, a ring gear member 14C and a planet gear carrier member 14B that
rotatably supports a set of planet gears 14D (only one of which is
shown). The sun gear member 14A is connected for common rotation with a
first shaft or interconnecting member 42. The ring gear member 14C is
connected for common rotation with the input shaft or member 12. The
planet carrier member 14B is connected for common rotation with a second
shaft or interconnecting member 44. The planet gears 14D are each
configured to intermesh with both the sun gear member 14A and the ring
gear member 14C.

[0035] The planetary gear set 16 includes a sun gear member 16C, a ring
gear member 16A and a planet gear carrier member 16B that rotatably
supports a set of planet gears 16D (only one of which is shown). The sun
gear member 16C is connected for common rotation with a third shaft or
interconnecting member 46. The ring gear member 16A is connected for
common rotation with a fourth shaft or interconnecting member 48. The
planet carrier member 16B is connected for common rotation with the fifth
shaft or interconnecting member 52. The planet gears 16D are each
configured to intermesh with both the sun gear member 16C and the ring
gear member 16A.

[0036] The planetary gear set 18 includes a sun gear member 18C, a ring
gear member 18B and a planet gear carrier member 18A that rotatably
supports a first set of planet gears 18D (only one of which is shown) and
a second set of planet gears 18E (only one of which is shown). The sun
gear member 18C is connected for common rotation with the second shaft or
interconnecting member 44 and a sixth shaft or interconnecting member 54.
The ring gear member 18B is connected for common rotation with a seventh
shaft or interconnecting member 56. The planet carrier member 18A is
connected for common rotation with the fifth shaft or interconnecting
member 52 and with an eighth shaft or interconnecting member 58. The
first set of planet gears 18D are each configured to intermesh with both
the sun gear member 18C and the second set of planet gears 18E. The
second set of planet gears 18E are each configured to intermesh with both
the ring gear member 18B and the first set of planet gears 18D.

[0037] The planetary gear set 20 includes a sun gear member 20C, a ring
gear member 20A and a planet gear carrier member 20B that rotatably
supports a set of planet gears 20D (only one of which is shown). The sun
gear member 20C is connected for common rotation with a ninth shaft or
interconnecting member 60 and with a tenth shaft or interconnecting
member 62. The ring gear member 20A is connected for common rotation with
a fourth shaft or interconnecting member 48. The planet carrier member
20B is connected for common rotation with the seventh shaft or
interconnecting member 56 and with the output shaft or member 22. The
planet gears 20D are each configured to intermesh with both the sun gear
member 20C and the ring gear member 20A.

[0038] The input shaft or member 12 is continuously connected to an engine
(not shown) or to a turbine of a torque converter (not shown). The output
shaft or member 22 is continuously connected with the final drive unit or
transfer case (not shown).

[0039] The torque-transmitting mechanisms or clutches 24, 26, 28 and
brakes 30, 32 and 34 allow for selective interconnection of the shafts or
interconnecting members, members of the planetary gear sets and the
housing. For example, the first clutch 24 is selectively engageable to
connect the eighth shaft or interconnecting member 58 with the tenth
shaft or interconnecting member 62. The second clutch 26 is selectively
engageable to connect the sixth shaft or interconnecting member 54 with
the tenth shaft or interconnecting member 62. The third clutch 28 is
selectively engageable to connect the input shaft or member 12 with the
ninth shaft or interconnecting member 60. The first brake 30 is
selectively engageable to connect the fourth shaft or interconnecting
member 48 with the stationary element or the transmission housing 50 in
order to restrict the member 48 from rotating relative to the
transmission housing 50. The second brake 32 is selectively engageable to
connect the third shaft or interconnecting member 46 with the stationary
element or the transmission housing 50 in order to restrict the member 46
from rotating relative to the transmission housing 50. The third brake 34
is selectively engageable to connect the first shaft or interconnecting
member 42 with the stationary element or the transmission housing 50 in
order to restrict the member 42 from rotating relative to the
transmission housing 50.

[0040] Referring now to FIG. 2 and FIG. 3, the operation of the ten speed
transmission 10 will be described. It will be appreciated that
transmission 10 is capable of transmitting torque from the input shaft or
member 12 to the output shaft or member 22 in at least ten forward speed
or torque ratios and at least one reverse speed or torque ratio. Each
forward and reverse speed or torque ratio is attained by engagement of
one or more of the torque-transmitting mechanisms (i.e. first clutch 24,
second clutch 26, third clutch 28, first brake 30, second brake 32 and
third brake 34), as will be explained below. FIG. 3 is a truth table
presenting the various combinations of torque-transmitting mechanisms
that are activated or engaged to achieve the various gear states. An "X"
in the box means that the particular clutch or brake is engaged to
achieve the desired gear state. An "O" represents that the particular
torque transmitting device (i.e. a brake or clutch) is on or active, but
not carrying torque. Actual numerical gear ratios of the various gear
states are also presented although it should be appreciated that these
numerical values are exemplary only and that they may be adjusted over
significant ranges to accommodate various applications and operational
criteria of the transmission 10. Of course, other gear ratios are
achievable depending on the gear diameter, gear teeth count and gear
configuration selected.

[0041] For example to establish a reverse gear, first clutch 24, first
brake 30 and third brake 34 are engaged or activated. The first clutch 24
connects the eighth shaft or interconnecting member 58 with the tenth
shaft or interconnecting member 62. The first brake 30 connects the
fourth shaft or interconnecting member 48 with the stationary element or
the transmission housing 50 in order to restrict the member 48 from
rotating relative to the transmission housing 50. The third brake 34 the
first shaft or interconnecting member 42 with the stationary element or
the transmission housing 50 in order to restrict the member 42 from
rotating relative to the transmission housing 50. Likewise, the ten
forward ratios are achieved through different combinations of clutch and
brake engagement, as shown in FIG. 3.

[0042] It will be appreciated that the foregoing explanation of operation
and gear states of the ten speed transmission 10 assumes, first of all,
that all the clutches not specifically referenced in a given gear state
are inactive or disengaged and, second of all, that during gear shifts,
i.e., changes of gear state, between at least adjacent gear states, a
clutch engaged or activated in both gear states will remain engaged or
activated.

[0043] The description of the invention is merely exemplary in nature and
variations that do not depart from the gist of the invention are intended
to be within the scope of the invention. Such variations are not to be
regarded as a departure from the spirit and scope of the invention.

Patent applications by Andrew W. Phillips, Rochester, MI US

Patent applications by Edward W. Mellet, Rochester Hills, MI US

Patent applications by James M. Hart, Belleville, MI US

Patent applications by GM GLOBAL TECHNOLOGY OPERATIONS LLC

Patent applications in class With brake for sun, carrier and orbit

Patent applications in all subclasses With brake for sun, carrier and orbit